The Carter administration expects to submit to Congress today the first comprehensive overhaul of U.S. refugee laws since 1952, according to State and Justice department officials.

The bill, written during five months of close consultation between the administration and the Senate Judiciary Committee staff, comes at a time when the number of refugees in Southeast Asia, Eastern Europe, Africa and Latin America has reached crisis proportions. There are now more people seeking permanent resettlement outside their homelands than at any time since the end of World War II.

The new legislation provides for a normal annual flow of at least 50,000 refugees a year into the United States, but the president, after consultation with Congress, could raise that figure before the beginning of any given year.

If an emergency situation arises, such as the surge of hundreds of thousands of refugees who have fled Vietnam, Laos and Cambodia in recent months, the president would also have the power to admit as many of them as he deemed of special concern to the United States. The legislation does not set a ceiling on the number who can be brought into the country under such circumstances.

Since World War II an average of about 40,000 refugees a year have been allowed into the United States, including the massive influxes after the Cuban revolution and the fall of Saigon.

The new legislation calls for considerable federal assistance in the relocation and resettlement of the refugees, including extensive educational programs. Most refugees would be eligible for federally subsidized welfare assistance for up to two yeas after their arrival, though past experience suggests that the vast majority are financially independent of government aid after a few months.

An administration study that accompanied a recent draft of the bill estimates the total cost to the taxpayer for refugee relocation and resettlement at just over $1 billion dollars over the next five years if the flow is kept to 50,000.

If the influx is 100,000 a year, however, the five-year cost would be about $1.7 billion.

The analysis suggests that "most of the same costs would be incurred in any event if a comparable number of refugee admissions were made available under existing law."

At present the only people who may be admitted under normal procedures are those fleeing communist regimes or the Middle East. As a result it has been extremely difficult for refugees from right-wing oppression to obtain asylum in the United States.

A proposed new definition of "refugee" would apply worldwide to anyone who is outside his or her country and unable or unwilling to return because of persecution, or a well-founded fear of it, stemming from race, religion, nationality, membership in a particular social group, or political opinion.

Because of the limited definition in the past, and the fact that only 17,400 refugees a year were allowed into the United States even if they met it, most refugees have had to come into the United States under the emergency "parole authority" of the attorney general.

This provision in the current law was originally intended to allow in only individual refugees under highly specialized circumstances -- not, as has been the practice since the mid-1950s, scores or even hundreds of thousands of displaced people at a time. Returned to its position as a limited measure, the parole authority remains a part of the administration bill.

Sen. Edward M. Kennedy (D-Mass.) has been a prime mover in attempts to revise refugee law. He and House Judiciary Committee Chairman Peter W. Rodino Jr. (D-N.J.) are expected to introduce the administration proposal.

"For too long our policy toward refugee assistance [has] been ad hoc and has lacked effective planning and efficient programming," Kennedy said recently. "We have admitted refugees in fits and starts because our immigration law has been inadequate, discriminatory and totally out of touch with today's needs."

Previous legislation was stalled in the Senate Judiciary Committee but Kennedy -- who is now to the committee chairman -- said that he is optimistic about passage of the administration's bill.

Currently there are at least 200,000 refugees in Indochina alone who would be affected by the legislation if it passes.

At present, both Australia and France accept more Indochinese refugees in proportion to their population than the United States does. Israel, Germany and Britain have all resettled large numbers of refugees for whom they feel they have special responsibilities.